Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 04, 2021	Jun. 30, 2020
Entity Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Amendment Flag	false
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2020
Current Fiscal Year End Date	--12-31
Document Period End Date	Dec. 31, 2020
Entity Central Index Key	0001156039
Entity File Number	001-16751
Entity Registrant Name	ANTHEM, INC.
Entity Incorporation, State or Country Code	IN
Entity Tax Identification Number	35-2145715
Entity Address, Address Line One	220 Virginia Avenue
Entity Address, City or Town	Indianapolis
Entity Address, State or Province	IN
Entity Address, Postal Zip Code	46204
City Area Code	(800)
Local Phone Number	331-1476
Title of 12(b) Security	Common Stock, Par Value $0.01
Trading Symbol	ANTM
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 66,230,779,383
Entity Common Stock, Shares Outstanding		244,905,689
Documents Incorporated by Reference	Part III of this Annual Report on Form 10-K incorporates by reference information from the registrant’s Definitive Proxy Statement for the Annual Meeting of Shareholders to be held May 26, 2021.